ZnSe (zinc selenide) is superior in characteristics of transmitting infrared light. Therefore, zinc selenide is employed in optical components, such as window material and lens material, of a carbon dioxide gas laser used for cut processing, sheet-metal processing, and the like. ZnSe employed in such optical components is formed to have various component shapes by synthesizing the material through a CVD method (also referred to as a chemical vapor deposition method, a chemical vapor phase growth method, or the like) and then applying machining, such as grinding and polishing, to the material.
The manufacturing cost for such optical components is highly dominated by the material cost and the machining cost. Reduction of these costs is important for the widespread use of optical components made of ZnSe. Machining such as grinding and polishing is not only time-consuming but also causes more or less waste of material in the form of machining chips due to cutting out a component shape from a large piece of material, leading to a rise in the manufacturing cost.
As a method for manufacturing an optical component made of ZnSe in a more inexpensive manner, there has been proposed a method of applying machining to a minimum extent. For example, WO2003/055826 (PTD 1) proposes a method of using a pressure/heat press to perform net-shape deformation to obtain a final shape from raw material powder. Further, Japanese Patent Laying-Open No. 05-043359 (PTD 2) proposes a method of press-molding a polycrystal body constituted by fine crystals.